1. Field of the Invention
This invention relates generally to the field of active vehicle protection systems and, more particularly, to a sensor controlled automatically deploying inflatable ballistic penetration resistant airbag system for protection of lightly armored vehicles against rocket propelled grenades (RPG) and other explosive rounds by active defusing to preclude detonation. Additional protection from small arms rounds is also provided by certain embodiments.
2. Description of the Related Art
Various armor systems are employed for protection of personnel and vehicles from small arms fire and shrapnel from anti-personnel mines or grenades. For both individuals and vehicles, the weight and other impediments of the armor dictate the type of armor used.
Fabric armor for self-protection and vehicular protection systems is employed on a regular basis since the development of products such as Kevlar® or other aramid fibers which provide highly resilient protection against ballistic projectiles. Vests, brief cases and similar personal protection items employ Kevlar® or comparable fabrics for light weight highly penetration resistant systems. Seats and vehicular body panels employ similar high strength woven fiber products in lightweight laminates for protection against ballistic penetration.
Recently, the concept of deployable shields using airbag technology to erect a temporary barrier for protection of speaker's podiums, windows, doorways and similar environments from small arms fire has been disclosed in U.S. Pat. Nos. 6,412,391 entitled Reactive personnel protection system and method issued Jul. 2, 2002 and 6,029,558 also entitled Reactive personnel protection system, both assigned to Southwest Research Institute. These systems employ airbag technology to erect a temporary shield against ballistic projectiles from small arms fire or bomb detonation.
It has become apparent that in addition to small arms fire, rocket propelled grenades (RPG) are a major threat to lightly armored vehicles. It is therefore desirable to employ deployable armor to intercept an RPG as well as protect against small arms fire.
Explosive armor is well known as a countermeasure against both kinetic energy rounds and explosively formed jets (EFJ's). Explosive armor of prior art may be too heavy to add to light armored vehicles and may expose dismounted troops to unnecessary risk. Hard armor sufficiently thick to absorb the explosively formed jet from an RPG is too heavy for light armored vehicles and may result in a sufficiently high weight to preclude air transport and the rapid deployment which may only be accomplished by air transport. Even the M1 Abrams tank may be demobilized by a RPG depending on point of impact. Chain link fence has been used with partial success against RPG's since the Vietnam Conflict. Direct impact of the piezo-electric fuse against a wire element of a chain link fence can be expected to cause function of the RPG in accordance with its design, i.e., detonation of the shaped charge and formation of the explosively formed jet. Such a jet may penetrate metal several meters distant and may be lethal at a distance of tens of meters. Various attempts have been made to use nets to catch or damage RPG's. A net sufficiently robust to crush the ogive portion of RPG's may be also be sufficiently stiff to cause detonation in the case the fuse directly impacts a net cord element. Such a robust net may also trap without further damage a piezo-electrically disabled RPG causing time delayed detonation immediately adjacent to the protected vehicle. At the time of this writing “bar armor” is being used by Coalition Forces in Iraq and Afghanistan with partial success against RPG's. Like chain link fence, bar armor can disable the piezo-electric fuse circuit by crushing the ogive as the RPG passes between bars. In the case of direct fuse impact against an individual bar, however, the RPG is likely to function with lethal as-designed EFJ formation. The bar armor may be somewhat better than chain link fence with respect to impact destruction of time delay fuse/high explosive remains of a piezo-electrically disabled RPG. Bar armor effectiveness against RPG's is estimated at 60%. Due to wide variation of azimuth angle and minimal variation in elevation angle of incoming RPG's, bar armor is typically constructed with horizontal bars. Horizontal bars result in a lower chance of direct piezo-fuse impact with a bar compared to vertical bars in the case of azimuth angles less than 90 degrees
It is desirable to deploy an armor system that will disable the RPG fusing mechanism to prevent detonation.
It is also desirable to absorb the impact of the RPG on the target vehicle after disabling the fusing mechanism.
It is further desirable to provide in certain applications a “soft catch” of an RPG launched against a vehicle to further avoid detonation and absorb kinetic energy of the round thereby reducing the potential damage to the vehicle and injury to personnel.